US2723875A - Magnetic devices - Google Patents

Description

Nov. l5, 1955 Filed Nov. 20, 1952 G. l.. RUSSELL 2,723,875

MAGNETIC DEVICES 5 Sheets-Sheet l Eli JNVENTOR.

Nov. l5, 1955 G, L, RUSSELL i 2,723,875

MAGNETIC DEVICES Filed Nov. 20, 1952 5 Sheets-Sheet 2 I l f 75 ME75 f 1 ll Nov. 15, 1955 G, 1 RUSSELL 2,723,875

MAGNETIC DEVICES Filed Nov. 20, 1952 5 Sheets-Sheet 3 W /yd [T1 L Q l l; .2.13

n l n -f/M IN VEN TOR. 6' .eo/rg@ z/Ssel lBY Y 2,723,875 Patented Nov. 15, 1955 United States Patentl Oiice MAGNETIC DEVICES Application November 20, 1952, Serial No. 321,570 27 claims. (ci. 294-655) This invention relates to magnetic lifting and feeding devices, and especially to manual devices for lifting, carrying and feeding metal sheets, bars or other objects in an efficient manner.

In the past, `manual lifting and feeding devices have been proposed which utilize the rubber suction cup principle. It has been found that such devices have many disadvantages which detract from their eciency. In normal use, for example, the engaging surface of the suction cup wears out rapidly and the cups must be replaced. The cups also tend to lose their'seal easily, and y'a chip or other foreign particle on the surface of the work will prevent a proper grip. Suction cups cannot be used when the work is perforated or has any hole or depression. The use of multiple cups forlifting larger workpieces llas also been unsuccessful, due to the dilculty of arranging the cups on a proper support. f

The permanent magnet principle has also been usedin the past in the construction of manual lifters and feeders, but here again the attempts have been generallyunsuccessful. In order to build a magnet device strong Venough to lift heavy objects, ease of releasing 'or detaching the magnet from the work has been sacrificed. O'nl Athe other hand, where these magnetic devices have been easy to remove, they have not been strongenough for general use. Furthermore', the use of a single large magnetifor lifting purposes increases the possibility of a foreign particle being caught under the engaging surface of thel magnet, thus preventing a proper grip from taki'ng'kplace. SuchV magnetic devices in the past have also hadlthe'disadvantage o f tending to slip along the work surface, thus ycreating a serious problem when sheets are to be transported from one location to another.

It is an objectof the present invention to overcome the disadvantages of previous types of lifters and feeders, and to provide a device using the permanent magnet principle,` which affords a strong and rm grip on the`-workpiece kand yet is relatively easy to release.' v "It is vanother object to provide a magnetic lifter and feeder .as described above, which iszeasy to apply Ato the workpiece and which includes means for insuringk a firm grip even if a foreignparticle should be encountered on the surfaceof the workpiece. n

It is afurther object to provide a magneticlifter and feeder of the above nature,'havingpafplurality of magnet assemblies spaced along a bar which can kbe manually grasped, and in which the encountering of a foreign particle by one of said assemblies will not decrease the eilicacy of the gripping, action of the other assemblies. It is ak further object to provide a magnetic lifter and feeder as'vdescribedabove, having means for preventing vsliding action of the'grips along the work surface, so that a firm grip is maintained even if the yworkpiece is tilted.

"It is Vanother objectto provide Aa magnetic lifter and feeder described above, in which means areprovided 'as part of each grip for aiding in the release of the device `from the workpiece',` the release being accomplished by`a twisting motionof the' handle bar.

It is also an object in several forms of the invention, to provide a magnetic lifter and feeder of the above character, in which each magnet lassembly includes a permanent magnet having'pole pieces and a housing, the housing also serving as separating means when it is desired to release the workpiece.

It is a further object, in other forms of the invention, to provide a magnetic lifter and feeder of the above nature, in whicheach magnetassembly includes a permanent magnet having pole faces which also serve as work-engaging surfaces and in which the pole pieces are eliminated, the housing which supports the permanent magnet also servingas separating Ameans when it is desired to release the workpiece. n

Other objects, features, and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

Figurel is a perspective view of a preferred embodiment of theinvention, showing two magnet assemblies in position on the bar;

Figure 2 is a side elevational view of the embodiment of Figure l, showing the manner in which the tool engages a workpiece to be lifted; AFigure 3 is a top plan view of the device, showingthe configuration of the barand magnet assemblies;

. Figure 4 is a cross-sectional View taken along the line 4,-4 of Figure 2, with parts broken away for clarity, show` ing the construction of the retaining clips andthe magnet housing;

n Figure 5 is a cross-sectional view taken along the line `5---5 of Figure 4 and showing the loose fit of the magnet housing on the bar, as well as the cross-sectional shape of the non-slip insert;

Figure 6 is a bottom plan view of one of the magnet assemblies, showing the engaging area of the non-slip insertg' 1 s t Figure 7 isa view similar to Figure 4, with the clip removed, showing a modified form of the magnet assembly having a housing formed of a strip of metal;

Figure 8 is a general side elevational View of another embodiment of the invention having a flexible bar, for purposes of gripping curved workpiece surfaces, the view showing a concave surface being engaged; f

l Figure 9 is a view `similar to Figure 8, but showing the `tool engaging a convex workpiece surface;

Figure `l0 is a side elevational view of still another em,- hodiment of the invention, having the handle arranged at the central portion of the bar which is especially adapted for lifting heavy objects;

Figure l1 is a side elevational view of still another embodiment of the invention which is especially adapted for lifting a plurality of separate objects such as cans which are arranged in a row; i

Figure l2 is a front elevational view of another form of magnet assembly using a horseshoe magnet, the pole faces of thev magnet 'also serving as work-gripping surfaces, the magnet assembly retaining clips being omitted for purposes of clarity;

Figure 13 is a side elevational view of the embodiment of Figure l2; v

Figure 14 is a front elevational view of another type of magnet assembly using a bar magnet, one side of the bar magnet functioning as a work-gripping surface; i

Figure ,15 is a side Velevational View of the embodiment of Figure 14;`

Figure 16 is afurtherpmodification of the magnet assembly,` using a bar magnet parallel with the longitudinal axis of the handle bar; j

Figure 17 is a side elevational view of the embodiment of Figure r16;

Figure 18 is a further modification showing a magnet i 'assembly of the type illustrated in Figures 16 'and '17 lbut of a shape adapted for low lclearance conditions;

Figure 19 is a side elevational view of the embodiment of Figure 18;

Figure 2O is another modification of 'the magnet a'ssembly, generally similar to that of Figure 14 bu't adapted for low clearance conditions; and

Figure 21 is a side elevational view ofthe embodiment of Figure 20.

Referring now to Figures l-6, the invention comprises in general a flat bar 21 having secured vat one end thereof a handle or grip 22, and a plurality of magnet assemblies generally indicated at 23 which are adjustably mounted on the bar in spaced relation. Bar 21 is made of any suitable non-magnetic material such as aluminum and is of such dimensions as to be substantially rigid in both directions of bending. The magnet assemblies 23 'are substantially identical, and although only two such assemblies are 'shown 'as being mounted on bar 21, it will be understood that any appropriate number of such 'assemblies could be so mounted, depending on the nature of the work.

Each magnet assembly 23 comprises a housing 24 of a suitable non-magnetic material. In the embodiment of Figures 1-6, this housing is shown as being `formed of a block of material and is of substantially rectangular shape. The upper central portion of the housing is provided with a rectangular aperture 25 through which bar 21 extends. For purposes to be described later, the dimensions of aperture 25 are such that bar 21 has a loose fit therein; that is, the width of the aperture 25 is somewhat greater than the 'width of the bar, and the height ofthe aperture somewhat greater than the thickness of the bar, so that the housing is loosely held by the bar.

The 'housing is also provided with a recess y26 of considerable 'size extending upwardly from the lower surface 2'7 thereof, the recess being of inverted U'shape. Within this recess is retained a permanent magnet 28 of cylindrical shape, the curvature of the upper end of the recesses corresponding to the curvature ofthe magnet. As shown in Figure 5, the length of the magnet is approximately equal to the thickness of housing 24, and a pair of pole pieces 29 and 31 of magnetic material are secured to opposite sides of the housing and engage the opposite 'sure faces of the magnet. Pole pieces 29 and 31 are of rectangular plate-like shape. and have work-engaging surfaces 32 and 33 respectively at the lower ends thereof. It is apparent that the reduction of flux area between the magnet-engaging and the work-engaging surfaces of the pole pieces will cause a very heavy ux density 'at the work engaging surface, thereby providing a powerful magnetic attraction for the workpiece. The magnet assemblies are therefore such as to have 'reduced reaching out power but greatly increased strength at close -quarters, and therefore exhibit very great resistance to a 'direct pull exerred perpendicularly to 'the surface grasped. Hoa/ever, the assemblies maybe 'easily disengaged by tipping rhein in any direction. Furthermore, the 'gripping power is considerably impaired by the presence 'of any foreign rrtatter between the pole pieces and the object gripped. lThe polepieces also serve to retain the magnet 28 within the housing, the pole pieces themselves being ksecured to the housing by a plurality of spaced rivets 321 of 'non-magnetic material, vor other fastening means. Y

It is important to observe that the work engaging surfac-es 32 and 33 of 'the pole pieces'project slightly beyond the lower surface 27 of the housing, so that the housing in no way interferes with 'the engagement of the work. The width of 'housing 24 however is substantially greater than the width of pole pieces 29 and 31.` The lower corners 35 of the housing therefore serve as lateral projections on each side of the pole pieces, and aid in removing the tool from the workpiece in a manner later described.

In order that the magnet assembly be prevented YfrOm slipping along the workpiece surface, means are provided -between the pole 'pieces for engaging the 'surface of the workpiece in such a manner that slipping will be minimized. In the illustrated embodiment, this means comprises a compressible sponge rubber pad 36 disposed as an insert between the pole pieces and within the recess 26, the insert being held in place by such means as cement. As shown, the inner end 37 of the rubber insert is curved to fit the adjacent surface of magnet 2S, and is recessed at 3S in the vicinity of lower rivet 34. The outer surface 39 of the insert projects slightly beyond the common plane of surfaces 32 and 33, so that when the latter are attracted 'to the workpiece surface, the pad will be cornpressed, providing a frictional grip on the workpiece which will resist slide-slipping. lIt should be observed that, as shown in Figure 6, the area over which surface 39 extends is considerable in relation to the area of pole piece surfaces 32 and 33. The edges of the rubber pad adjacent `the pole pieces may be beveled as shown at 41 to prevent interference with the pole pieces when the pad is compressed. If desired, the surface '39 can be of another form, and in particular a piece of emery cloth (not shown) cou-ldgbe secured to the rubber so as to be engageable with the workpiece. ln other cases rubber with a serrated surface, or hardened steel points set in the rubber could be used.

Means are provided forretaining the magnet assemblies in longitudinally spaced relation on bar 21. It will be understood Athat in order for the tool to operate most efficiently, the maximum possible magnetic flux should be available for the workpiece. It is therefore desirable to have the magnet assemblies so arranged that like poles are in adjacent relation. It is also beneficial to have the assemblies some distance apart, and in any case they should not be so close together as to have mutual distortion of the flux paths. ln the illustrated embodiment, `a pair of clips 42 are provided for each magnet assembly, the clips being arranged on opposite sides of the assembly 'to prevent a substantial movement along the bar. As shown, each clip, which is made of suitable non-magnetic material, Vis bent to form a ybar-engaging portion 43 in sliding engagementwith bar 21, and a retaining portion 44 extending downwardly alongside the pole piece. kFor purposes to be described, it is preferred that the clips 42 be slightly spaced away from the magnet assembly, so that the latter is allowed limited movement. lt will be noted that dueto the thickness of each clip, that is its dimension parallel to bar 2'1, the magnet assemblies are kept a -minimtim distance apart which is sufficient to prevent flux distortion.

In operation, the magnet assemblies A23 are adjusted along bar '21 to accommodate the size of workpiece to be lifted. As shown in Figure 2, the workpiece 45 is a 'steelplate having flat surfaces, *and the two magnet 'as- 'semblies 'are spaced so as to engage the workpiece at evenly spaced points, so as to properly distribute the 4lifting forces. yThe operator holds the tool by means of handle 22 and places the magnet assemblies against the workpiece 45. The pole piece engaging surfaces 32 and 33 of each magnet assembly will engage the workpiece, and as described above, if no foreign particles are encountered the resultant gripping force will have great 'resistance to separation in a direction normal to the surface. The b'ar 21 may then be lifted by means of (handle 22. and due to the rigidity of the bar only normal forces will be vexerted on the mutually engaged surfaces. The workpiece 45 may thus be easily lifted 'and manipulated. lt should be observed that the shape of the handle bar between the handle 22 and the iirst magnet assembly 23 does not affect the operation of the tool as long as the force exerted on the magnet assemblies is normal to the workpiece surface. This portion of the bar may therefore be shaped if desired to avoid obstructions in that area. Since the sponge rubber pads 36 are cornpressed, their surfaces 39 will engage the workpiece 'and prevent slipping of the magnet assemblies should the workpiece be tipped.

When it is desired to release the workpiece, the bar 21 may be twisted around its longitudinal axis by means of handle 22. This will exert a separating force on one side of each pole piece, and on the other side an engaging pressure which provides a lever action. An initial separation of the pole pieces from the workpiece will thus rbe easily accomplished. After this motion is started, one

danger of such decreased efficiency is lessened in the present invention is by providing a plurality of magnet assemblies of smaller capacity rather than a single magnet assembly of larger capacity.y Since the area engaged by each such magnet assembly is lessened, the chances of Yeach magnet assembly encountering a foreign particle is also lessened. Another means by which the tool is permitted to operate efliciently despite encountering chips or foreign particles is the provision of a loose fit for each of the magnet assemblies 23 on bar 21. As described above, the size of aperture 25 in each magnet assembly housing permits a limited tilting of the magnet assembly with relation to the bar in any direction.

Assuming that a chip is encountered by surface 33 of pole piece 31, this will cause canting of that particular magnet assembly with respect to the workpiece'. If the magnet assemblies were rigidly connected to the bar, such a condition would prevent engagement of theother magnet assembly 23 with the workpiece, since the bar 21 would also be tilted. However, since in this case the t.

aperture 25 permits tilting of any magnetpassembly relative to the bar 21, the assembly whichlencounters the chip will be tilted without affecting the remaining assembly or assemblies. Thus, the tool will still be capable of efliciently engaging the workpiece despite the loss of efliciency in any particular magnet assembly. Another advantage of the special mounting means for the magnet assemblies described above is that workpieces having slightly irregular surfaces can be efficiently engaged by the tool,'since the play allowed for each magnet assembly on the bar will permit the tool to accommodate itself to the surface irregularities. Still another advantage of the loose connection between the magnet assemblies and the handle bar is the fact that the tool can be applied to the work without careful attention to the parallelism of the bar and work surface. should be at a slight angie relative to the work surface when it is lowered, the magnet assemblies, by tilting relative to the bar, will rmly attach themselves to the work.

Figure 7 illustrates a modied form of the invention in which a bent strip 46 of non-magnetic material replaces ,the housing member 24 of the embodiment of Figures 1-6. As shown, the strip 46 is formed with a pair of lower projections 47 which serve the purpose of corners of housing 24; The lower surfaces 48 of these projections are of course slightly above the engaging surfaces l49 of pole pieces 51. The latter are held against the vertical portions 52 of the strip by an appropriate cementitious substance 53 which lls the space between the sides of the housing strip. This ller also serves to position the cylindrical magnet 54. The `upper portion of the housing strip is formed as shown at 55 to form, with the upper edges 56 of the pole pieces, an aperture for the reception of bar 57. As in the previous embodiment ak space 58 is provided between the bar and its aper- In other words, even if the bary d ture so as to permit limited tilting movement of the mag'- net assembly in either direction. Also as in the previous embodiment, a sponge rubber pad insert 59 is provided having a lower engaging surface 61 projecting slightly beyond the Apole piece engaging surfaces 49. The embodiment of Figure 7 has the advantage underecertain conditions of being cheaper to manufacture than the previous embodiment, without detracting from the efciency of the tool.

Figures 8 and 9 illustrate another embodiment of the invention which differs from the previous embodiments in'that the bar 62 is flexible instead of being rigid.r In this manner the magnet assemblies 63 can be caused to firmly engage a workpiece 64 having a concave engaging surface or a workpiece 65 having a convexengaging surface. The principles of operation of the device, other than lthe flexible properties of the bar, are the same as for the previous embodiments. y

Figure 10 illustrates still another embodiment of the invention which is especially adapted to lift vrelatively heavy workpieces, where the lifting forces must be vmore equally distributed over the work. As shown, the bar 66 is provided with a handle 67 secured to its central portion, with magnet assemblies 68 disposed ony either side of the handle. The magnet assemblies are engageablel with a relatively heavy workpiece 69 adjacent either end thereof, with the handle 67 centrally located with respect to the work. In this manner, the loads imposed on magnet assemblies 63 will be approximately equal, so that each assembly need only be strong enough to carry half the total weight, and the operator will have a balance of forces at handle 67. Of course, the bar 66 may be made of any desired length, with additional magnet assemblies 68 mounted thereon so as to lift any given size of workpiece. Figure ll illustrates a further embodiment of the in vention which is especially adapted for lifting a plurality of metallic containers or similar objects which are arranged in a row. For example, this embodiment may be useful where it is desired to remove rows of cans from a carton and to place the cans on a storage or display shelf. As shown, the embodiment has a handle' bar 71 with a hand grip 72 detachably secured thereto. and a plurality of magnet assemblies 73 mounted on tue nandle bar at evenly spaced intervals. In order that the handle bar be made long enough to pick up a complete row of cans, the hand grip 72 is attached to the handle bar by means of a bracket 74 extending parallel to the handle bar and having downturned outer portions y'75. The inturned ends 76 of these outer portions are detachably secured to the handle bar by bolts 77. In this manner the magnet assemblies 73 may be slidably adjusted along the handle bar by temporarily detaching one or both ends of bracket 74. The row of cans 78 may then be simultaneously picked up merely by lowering the tool over the row of cans. The other principles of operation ofthe device are similar to those of the preceding embodiments, and it will be noted that due to the play of magnet assemblies 73 on the handle bar, slight variations in the height of the cans due to their packing condition will not affect operation ofthe tool. v

Figures l2 and 13 illustrate another form of magnet assembly which eliminates the pole pieces of the previous embodiments and utilizes the pole faces of the magnet as' the work-gripping surfaces. In this embodiment, a horseshoe magnet 79 having pole faces 81 and 82 is cemented or otherwise secured to a recessed supporting block 83 of non-magnetic material, the block having a slot 84 for the reception of the handle bar 85 as in the previous em bodiments. The lower corners 86 of the housing project laterally and the lower surface 87 of the housing is slightly above the level of the pole faces. The housing therefore serves as a releasing means for removing the tool from the workpiece, as in the previous embodiments. It will be noted that this arrangement entirely eliminates the necessity -for separate ,pole piece members, since -themasnet .pole 'facesserve also as work-.gripping surfaces.

@Figures 14 .and .15 illustrate `another form .of tmagne't .assembly vusinga bar magnet 88, `preferably magnet'zed as .a horseshoe magnet .and held within a non-magnetic .supporting .block 89, the .supporting block 'having a slot 9:1 for receiving the handle bar l92. The longitudinal axis of the .barmagnetis arranged at .right angles to the handle bar, so that the lower surface V93 vof lthe magnet .serves as a :work-.gripping surface similar to those of the polepiecesin.theprevious embodiments. The supporting lockzhas -laterally extending lower corners 94, the level .of which is slightly above .the work-gripping surface of .the magnet, .these corners therefore .serving as vreleasing means :forthe tool.

Figures .16 4and ..17 illustrate .another form of magnet .assembly .in .which .the bar magnet 95 is arranged with its longitudinal axis parallel .to the handle bar 96. In this embodiment, .the .supporting housing97 is of a length corresponding approximately -to .the length of the bar l magnet, Athe lowersurface 980i which serves as a work- :gripping surface. As in the .previous embodiment, the sidecorners .99 ofthe supportinghousing serve as releas- .ing means .for .the magnet. This arrangement Vis especially adapted .for .handling workpieces such as narrow strips, and it will .be noted that because of the pole arrangement less torque willbe required to release the workpiece., ythuspermitting the use of a thinner-and narrower handle'bar.

Figures .18 and 19 illustrate another form of .magnet assembly generally similar to that of Figures 16 and .17, vbutin which .the height H of the supporting housing 101 is considerably less than the width W of the housing. .The .bar magnet 102 is likewise of .flat construction, and the resultant shape will permit the tool to be inserted in spaces having low clearance.

Figures 2O and 2l illustrate a further form .of the mag- .net assembly generally similar to that of Figures 14 and 15, ibut in which the height 'H' ofthe housing 103 is considerably less than the width W. The magnet 104 is .made of suicient length to extend across .the major por- .tion of thehousing and the resultant shape of the magnet .assembly is, like the embodiment of Figures 18 and 19, especially .adapted for handling workpieces under low clearance conditions.

While it will -be .apparent that the .preferred .embodi- .ments of theinventionherein disclosed are well calculated to fulfill the objects 'above stated, it will be appreciated .that `the .invention .is .susceptible to modification, variation 'and change without departing from the proper scope or ffair meaning ofthe subjoined claims.

Vhatis claimed is:

1. -In ,a magnetic tool, .ahandleban a magnet assembly mounted .on .said bar, .said assembly including a magnet .and .a pair .of polepieces on .opposite sides thereof, work engaging surfaces at one end of .said pole pieces, said engaging surfaces being in a common plane, and a portion on said magnet assembly extending to one side of vsaid .pole pieces, said extending portion being slightly above said common plane, whereby said portion is adapted to engage .the work when said pole pieces are vtilted slightly fromthe'ir engagement with the work.

2. In amagnetic tool, a handle bar, a magnet assembly including a magnet and a pair vofjpole pieces 'at opposite sides of said magnet and `adapted to engage a workpiece, and fmeans 2for v`slidably mounting said magnet assembly pon .said handle bar, -sad means including lan apertured `portion adapted .to receive the handle bar therethrough, .said Aapertured portion being .of .slightly larger size than Isaid handle bar., -whereby said 'magnet assembly can .have .limited tilting movement with respect to said bar.

3. .In a magnetic tool, a handle bar, a magnet assembly including amagnet and apair of pole pieces .adjacent the magnet and having work engaging surfaces .ina common plane, aiportion on said magnet assembly extending outlil mounted'on saidhandle bar, said magnet assembly including .a magnet vanda pair of pole .pieces .having work engaging surfaces .in a commonplane, .and a yieldable workTgripping .insert .disposed between .said Apole .p'ieces, said insert having a work .engaging portion zprojecting beyond said common plane and adapted .to .resist 'sliding movement of the work onsaid polepieces. i

5. ln a magnetic tool,.a handle bar,.a magnet assembly mounted on said handle bar, said .magnet .assembly including a magnet and a pair of pole 'pieces .having work engaging surfaces .in a common plane, a `yieldable workgripping insert disposed between said .pole pieces, said insert having a Work engaging portion-projecting beyond said common plane and adapted to .resist sliding movement of the work on said .pole pieces, and a portion on said magnet assembly extending 'to one side .of said .pole pieces, said extending portion vbeing slightly above .said common plane, whereby said portion is adapted to lengage the work when said Ipole pieces are tilted slightlyfrom their engagement with the work.

6. ln a magnetic tool, a handle bar, a magnet assembly including a magnet `and a pair of pole pieces at vopposite .sides of said magnet and adapted to engage a workpiece,

means for slidably mounting said .magnet assembly on said handle bar, said means including an apertured portion adapted to receive the handle bar therethrough, said apertured portion being of slightly larger size than said handle bar, whereby said magnet assembly can :have limited tilting movement with respect to said bar, and -a pair of retaining elements on said handle bar for limiting sliding movement of the magnet assembly thereon, said retaining elements permitting said limited `tilting movement to take place.

7. In a magnetic tool, .a rigid handle bar vof rectangular cross-section andhaving a handle secured thereto, a magnet assembly includinga magnet and a pair of pole-pieces at opposite .sides of said .magnet and .adapted to engage-a workpiece, and means `for slidably mounting 'saidmagnet assembly on said handle bar, said means including aan apertured portionadapted to Vreceive the handle barfthcrethrough, said apertured portion being of slightly :larger size than said handle bar, whereby said .magnet asscmbly can have limited tilting .movement with .respect lto said bar.

8. In a magnetic tool, a rigid handle bar, hand gripping means on said bar, a magnet assembly includinga housing formed of a blockrof nonmagneticmaterial, an 'apertured portion in said block of slghtlyflar-,ger proportions Vthan said handle bar for receiving the handle bar therethrough, a magnet held in said block, the length of said magnet being approximately equal to the thickness'of lthe block, and a pair of pole pieces secured to opposite sides of said block, said polepieces .having relatively large areas facing the ends of said magnet and relatively small work engaging surfaces yin a vcommon plane, said lblock having port1ons extending outwardly beyond thesides Vof said 'pole pieces, said vportions being slightly above said t.common plane.

9. In amagnetic tool, a rigid handle bar, hand gripping means on said bar, -a magnet assembly including a`fhous ing formed .of a .block of non-magnetic .'material, fan apertured portion in .said block of .slightly .larger .proportions .than said `handle bar for receiving the .handle bar therethrough, a magnet held in said block, the length of said magnet being approximately equal to the thickness of the block, a pair of pole pieces secured to opposite sides of said block, said pole pieces having relatively large areas facing the ends of said magnet and relatively small work engaging surfaces in a common plane, said block having portions extending outwardly beyond the sides of said 'pole pieces, said portions being slightly above said common plane, and a compressible insert disposed between said pole pieces, said insert having a work engaging surface projecting beyond said common plane when in its uncompressed state.

v10. In a magnetic tool, a rigid handle bar, hand gripping means on said bar, a magnet assembly including a housing formed of a block of non-magnetic material, an apertured portion in said block of slightly larger proportions than said handle bar for receiving the handle bar therethrough, a magnet held in said block, the length of said magnet being approximately equal to the thickness of the block, a pair of pole pieces secured to opposite sides of said block, said pole pieces having relatively large areas facing the ends of said magnet and relatively small work engaging surfaces in a common plane, said block having portions extending outwardly beyond the sides of said pole pieces, said portions being slightly above vsaid common plane, and a plurality of rivets extending through said housing outwardly of said magnet and securing said pole pieces in place.

11. In a magnetic tool, a handle bar having gripping means thereon, a plurality of magnet assemblies on said handle bar, each magnet assembly including a magnet, pole pieces adjacent the opposite ends of said magnet and having work engaging surfaces in a common plane,

means for mounting each of said magnet assemblies on said bar, and means for retaining said magnet assemblies in spaced relation on said bar.

12. In a magnetic tool, a substantially rigid handle bar, a plurality of magnet assemblies, each of said assemblies including a magnet, a pair of pole pieces on opposite sides of said magnet and having work engaging surfaces in a common plane, and mounting means for said magnet assembly, said mounting means allowing each of said magnet assemblies to have limiten movement independent of said handle bar.

13. The combination according to claim l2, said handle .bar being further provided with retaining elements for v holding each of said magnet assemblies in an adjusted position along said handle bar.

14. In a magnetic tool, a rigid handle bar, a hand grip secured to a central' portion of said handle bar, and a plurality of magnet assemblies mounted on opposite sides of said bar, each of said magnet assemblies including a magnet, pole pieces having relatively large areas adjacent the magnet poles and relatively small work engaging surfaces in a common plane, mounting means for each of said magnet assemblies permitting limited tilted movement of each magnet assembly independent of the bar, said mounting means including an apertured portion in each magnet assembly through which said bar extends, said apertured portion being of slightly larger size than said bar, a nonmagnetic portion extending from each of said magnet assemblies slightly above the plane of said work engaging surfaces, whereby said portion is adapted to engage the work when said work engaging surfaces are tilted slightly from engagement with the work, and means for adjustably retaining each of said magnet assemblies in position on said bar.

15. In a magnetic tool, a rigid handle bar of nonmagnetic material, a hand grip, a bracket for securing said hand grip to said handle bar, said bracket having portions releasably secured in spaced relation on said bar, a plurality of magnet assemblies slidably mounted on said bar, said bracket being detachable from said bar to permit at least one of said magnet assemblies to be slid to a position between the attaching portions of said bracket, means for retaining each of said magnet assemblies in positioneach of said magnet assemblies including a permanent magnet, pole pieces adjacent said magnet and having work engaging surfaces in a common plane, apertured means on the magnet assembly for receiving said handle bar therethrough, the size of said aperture being slightly greater than said bar, whereby limited tilting movement of each magnet assembly with respect to the bar is permitted, and a nonmagnetic portion extending from the magnet assembly slightly above the plane of said work engaging surfaces, whereby said last-mentioned portion is adapted to engage the work when the work engaging surfaces are tilted slightly from their engagement with the work.

16. In a magnetic tool, a handle bar, a magnet assembly mounted on said bar, said assembly including a magnet and pole faces at opposite ends thereof, said faces serving as work-engaging surfaces and being in a common plane, and a portion on said magnet assembly extending to one side of said pole faces, said extending portion being slightly above said common plane, whereby said portion is adapted to engage the work when said pole faces are tilted slightly from their engagement with the work.

17. In a magnetic tool, a handle bar, a magnet assembly including a magnet and pole faces on opposite ends thereof adapted to engage a workpiece, and means for slidably mounting said magnet assembly on said handle bar, said means including an apertured portion adapted to receive a handle bar therethrough, said apertured portion being of slightly larger size than said handle bar, whereby said magnet assembly can have relative tilting movement with respect to said bar.

18. In a magnetic tool, a handle bar, a magnet assembly mounted on said bar, said assembly including a magnet and pole faces at opposite ends thereof, said faces serving as work-engagingV surfaces and being in a common plane, a portion on said magnet assembly extending to one side of said pole faces, said extending portion being slightly above said common plane, whereby said portion is adapted to engage the work when said pole faces are tiltedy slightly from their engagement with the work, and means for slidably mounting said magnet assembly on said handle bar, said means including an apertured portion adapted to receive a handle bar therethrough, said apertured portion being of slightly larger size than said handle bar, whereby said magnet assembly can have relative tilting movement with respect to said bar.

19. In a magnetic tool, a handle bar, a magnet assembly mounted on said handle bar, said magnet assembly including a magnet provided with pole faces which constitute workengaging surfaces in a common plane, and a yieldable work-gripping insert disposed between said pole faces, said insert having a Work-engaging portion projecting beyond said common plane and adapted to resist sliding movement of the work on said pole faces.

20. In a magnetic tool, ahandle bar, a magnet assembly including a magnet the pole faces of which constitute Work-engaging surfaces, means for slidably mounted said magnet on said handle bar, said means including an apertured portion adapted to receive said handle bar therethrough, said apertured portion being of slightly larger size than said handle bar, whereby said magnet assembly can have limited tilting movement with respect to said bar, and a nonmagnetic portion extending from said magnet slightly above the plane of said work engaging surfaces, whereby said last-mentioned portion is adapted to engage the work when said work engaging surfaces are tilted slightly from engagement with the work.

21. In a magnetic tool, a handle bar, a magnet assembly including a horseshoe magnet the pole faces of which are adapted to engage a workpiece, means for slidably mounting said magnet assembly on said handle bar, said means including an apertured portion adapted to receive the handle bar therethrough, said apertured portion being of slightly larger size than "said handle bar, whereby said magnet assembly ean have limited tilting movement with respect to said bar, and a portion extending from said magnet assembly slightly above the plane of 'said pole pieces, whereby said last-mentioned portion is adapted to engage 'the work when said pole faces are tilted slightly from their engagement with the Work.

22. ln a magnetic tool, a handle bar, a magnetic assembly including a bar magnet extending transversely to sa'id handle bar, the side of said bar magnet away from said handle bar constituting a work engaging surface, means for slidably mounting said magnet assembly on "said handle bar, said means including an apertured 'portion adapted to receive thehandle bar therethrough, "said 'apertured 'portion being of slightly larger size than said handle bar, whereby said magnet assembly can have limited 'tilting 'movement 'with respect to said bar, and 'a nonmagnetic 'portion extending 'from said magnet assembly slightly above the plane of said work engaging surface, whereby said last-mentioned portion is adapted to engage the work when said work engaging surface is 4'tilted from its engagement with the Work.

23. -In a magnetic tool, a handle bar, a magnet assembly mounted on said bar, said assembly including a bar magnet extending parallel to said handle bar, the 'side of said bar magnet away from said handle bar constituting a work engaging surface, means 'for slidably 'mounting said magnet assembly on said handle bar, said means including an apertured portion adapted to receive the 'handle bar `therethrough, said apertured portion being of 'slightly larger size than said handle bar, whereby said magnet assembly can have limited tilting movement with respect 'to said bar, and a non-magnetic portion extending from said magnet assembly slightly above the plane of said work engaging surface, whereby said last-mentioned portion is adapted to engage the work when said work engaging surface is tilted slightly from its engagement with the work.

24. *ln a magnetic tool, a handle bar, a magnet having CJI -a work engaging surface, and means for loosely mounting 'said magnet on said handle bar, said means including an aperitured portion on said magnet adapted to receive ay handle bar therethrough, said apertured portion being of slightly larger size than said handle bar, whereby said magnet can have limited tilting movement with respect to said bar.

25. In a magnetic tool, a handle bar, a magnet mounted on said handle bar and having a work engaging surtace, and a nonmagnetic portion extending from said magnet, said nonmagnetic portion being slightly above the plane of said work engaging surface, whereby said portion is adapted to engage the work when said work engaging surface is tilted slightly from its engagement with the Work.

26. ln a magnetic tool, a handle bar, a magnet having a wort; engaging surface, means for loosely 'mounting said magnet on said handle bar, said means including an aperturcd portion on said magnet adapted to receive the handle bar therethrough, said ape'rtured portion being oi' Vslightly larger size than said handle bar whereby said magnet assembly can have limited tilting movement with respect to said bar, and a nonmagnetic portion extending from said magnet, said nonmagnetic portion being slightly above the plane of said work engaging surface, whereby said nonmagnetic portion is adapted to engage the work when said work engaging surface is tilted slightly 'from its engagement with the work.

27. The combination according to claim 24, the crosssectional shapes of said handle bar and aperture `being non-circular.

References Cited in the iile of this patent UNTTED VSTATES PATENTS 2,405,655 Kehoe Aug. 13, 1946 FOREIGN PATENTS 311,343 Germany .Tuly 2l, 1917

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